IOC(一). IOC容器初始化過程 -> AnnotationConfigApplicationContext.this()方法

一. 初始化兩個掃描器,並且價值基礎的註解過濾器的BeanPostProcessor的bean定義 --—> this()

1. this.reader = new AnnotatedBeanDefinitionReader(this); 註解讀取器，注入了基本的processor Bean定義

this.beanNameGenerator = new AnnotationBeanNameGenerator();  // 名字生成器
this.scopeMetadataResolver = new AnnotationScopeMetadataResolver();  // 註解範圍
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
Assert.notNull(environment, "Environment must not be null");
this.registry = registry;  // 當前context，也是個BeanDefinitionRegistry
this.conditionEvaluator = new ConditionEvaluator(registry, environment, (ResourceLoader)null);
AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);  // 注入核心註解的處理器

核心爲 AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);調到registerAnnotationConfigProcessors方法

public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(BeanDefinitionRegistry registry, Object source) {
    DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);  //當前context也是DefaultListableBeanFactory
    if (beanFactory != null) {
        if (!(beanFactory.getDependencyComparator() instanceof AnnotationAwareOrderComparator)) {
            beanFactory.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
        }

        if (!(beanFactory.getAutowireCandidateResolver() instanceof ContextAnnotationAutowireCandidateResolver)) {
            beanFactory.setAutowireCandidateResolver(new ContextAnnotationAutowireCandidateResolver());
        }
    }

    Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet(8);  // 固定8個
    RootBeanDefinition def;
    if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalConfigurationAnnotationProcessor")) {//internalConfigurationAnnotationProcessor配置註解Processor,是個BeanDefinitionRegistryPostProcessor
        def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalConfigurationAnnotationProcessor"));
    }

    if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalAutowiredAnnotationProcessor")) {// Autowired註解處理器， 是個InstantiationAwareBeanPostProcessorAdapter
        def = new RootBeanDefinition(AutowiredAnnotationBeanPostProcessor.class);
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalAutowiredAnnotationProcessor"));
    }

    if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalRequiredAnnotationProcessor")) {// required註解處理器
        def = new RootBeanDefinition(RequiredAnnotationBeanPostProcessor.class);
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalRequiredAnnotationProcessor"));
    }

    if (jsr250Present && !registry.containsBeanDefinition("org.springframework.context.annotation.internalCommonAnnotationProcessor")) {  // jsr250的，如postConstruct，是個InitDestroyAnnotationBeanPostProcessor
        def = new RootBeanDefinition(CommonAnnotationBeanPostProcessor.class);
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalCommonAnnotationProcessor"));
    }

    if (jpaPresent && !registry.containsBeanDefinition("org.springframework.context.annotation.internalPersistenceAnnotationProcessor")) {
        def = new RootBeanDefinition();  // internalPersistenceAnnotationProcessor,數據庫JPA支持

        try {
            def.setBeanClass(ClassUtils.forName("org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor", AnnotationConfigUtils.class.getClassLoader()));
        } catch (ClassNotFoundException var6) {
            throw new IllegalStateException("Cannot load optional framework class: org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor", var6);
        }

        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalPersistenceAnnotationProcessor"));
    }

    if (!registry.containsBeanDefinition("org.springframework.context.event.internalEventListenerProcessor")) { // 事件監聽
        def = new RootBeanDefinition(EventListenerMethodProcessor.class);
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.event.internalEventListenerProcessor"));
    }

    if (!registry.containsBeanDefinition("org.springframework.context.event.internalEventListenerFactory")) {
        def = new RootBeanDefinition(DefaultEventListenerFactory.class); // DefaultEventListenerFactory
        def.setSource(source);
        beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.event.internalEventListenerFactory"));
    }

    return beanDefs;
}

以上爲AnnotatedBeanDefinitionReader初始化核心

2. 類路徑掃描器：this.scanner = new ClassPathBeanDefinitionScanner(this);

this.beanDefinitionDefaults = new BeanDefinitionDefaults();
this.beanNameGenerator = new AnnotationBeanNameGenerator();
this.scopeMetadataResolver = new AnnotationScopeMetadataResolver();
this.includeAnnotationConfig = true;
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
this.registry = registry;
if (useDefaultFilters) {
    this.registerDefaultFilters();  // 搞了filter
}


this.setEnvironment(environment);
this.setResourceLoader(resourceLoader);

以上流程中都沒有實例化bean，全部都是bean定義